A 60-year-old man presents with dizziness, nausea and severe shoness of breath of several months' duration. Physical examination shows hepatomegaly, ascites and anasarca. His blood pressure is 200/115 mm Hg. An X-ray film of the chest demonstrates cardiomegaly and mild pulmonary edema. Although different mechanisms may have contributed to the pathogenesis of hypeension in this patient, the common end result for all of them is which of the following?